2026-02-23
Kirsten V. K. Gilardi, Brooke N. Genovese, Laurie A. Harris, Michael Cranfield, Jean Bosco Noheri, Antoine Mudakikwa, Dawn Zimmerman, Jean Felix Kinani, Methode Bahizi, Tierra Smiley Evans, Tracey Goldstein, Jonna A. K. Mazet
Morbidity and mortality from infectious diseases are an important health consideration for free ranging great apes, and respiratory illness (RI) is of particular concern in mountain gorillas (Gorilla beringei beringei), accounting for 25% all of mortalities. In addition to ongoing efforts to determine the etiology of RI in mountain gorillas, an improved understanding of environmental and demographic risk factors for the development of RI is critical for informing a disease prevention strategy for this species. To evaluate potential risk factors for RI, data were compiled from medical and life history records on free-ranging human-habituated mountain gorillas in Rwanda over a 7-year period from December 2005-December 2012. Associations between demographic, environmental and management risk factors and the presence of signs of clinical RI were evaluated using a multivariable mixed-effects logistic regression model. Clinical records from 21 habituated gorilla family groups, including 346 individuals, were included in analyses. Seventy-one percent of groups (n=15/21 gorilla groups) and 55% of individuals (n=192/346 gorillas) experienced at least one RI event. Rainy season (odds ratio [OR]=2.30, 95% CI = 1.74-3.03, P-value<0.001) and group size (OR = 1.15, 95% CI = 1.11-1.18, P-value<0.001) were associated with increased odds of RI in mountain gorillas, and there was a significant trend of increasing odds of RI with increasing group size for groups larger than 16 individuals and a more than 3-fold increase in odds of RI for groups larger than 38 individuals compared to groups of ten or less.
DOI: 10.3389/fcosc.2025.16854382026-02-04
Marcus Elfström, Emma Håkansson, Jan Olof Helldin
Underpasses have a fundamental potential in mitigating infrastructure barriers for wildlife, considering that they are a relatively common feature across traffic networks. Increasing our understanding of the functionality of the different designs and localities of underpasses is therefore crucial within infrastructure planning and management. We analyzed crossing probability, based on movement-triggered automatic cameras, in moose (Alces alces) and roe deer (Capreolus capreolus), common wild ungulates in Scandinavia, in relation to underpasses with different designs and localities. We analyzed the design through passage width, height, and length, including different combinations of these size dimensions. We also categorized underpasses into three size levels considering all dimensions. We included the nearest distance to the alternative crossing site while controlling for season, group size, and whether wildlife visits occurred during daytime or nighttime. We compared 797 visits by moose across nine underpasses and 1,433 visits by roe deer across 13 underpasses. Increasing tunnel length lowered the crossing probability in both moose and roe deer. Tunnel length not exceeding 16.5 m had a crossing probability above 50% in moose, whereas tunnel length not exceeding 12.0 m had a crossing probability above 50% in roe deer. However, we found no correlation between crossing probability and passage width and height. Tunnel length may describe a perceived narrowness more efficiently than other size dimensions. In roe deer, crossing probability increased when alternative crossing sites were situated further away, whereas moose showed a tendency toward the same pattern. Nearest distances to alternative crossing sites farther away than 1,150 m were related to more than 50% probability of roe deer visits resulting in crossing through underpasses. Thus, we conclude that tunnel length (ranging from 7.0 to 39.0 m) and nearness to alternative sites to cross seem to be more important factors than other size dimensions among underpasses (with passage width ranging from 2.8 to 42.0 m and passage height ranging from 2.0 to 10.2 m) to explain crossing probability in wild ungulates. The impact on crossing probability from the availability of other crossing sites stresses the importance of securing crossing opportunities along infrastructure barriers at the home range scale of focal species.
DOI: 10.3389/fcosc.2026.17514152026-01-30
Nuria Navarro, Andrea Suárez-Serrano, Christian Golcher, Pablo Flores, Pablo Martínez de Anguita
This article explores the potential existence of a conceptual “River Transition Curve” model in water quality and community-based river management, using Costa Rica and Honduras as case studies. It draws parallels to the well-established Forest Transition Curve, which describes how forest cover changes over socio-economic development stages: initial deforestation, stabilization, and eventual reforestation. It is proposed that a similar pattern may exist for rivers, linking water quality and river health to economic development and land use change. Therefore, understanding the temporal evolution of rivers, comparable to forest transitions, could inform more effective watershed management policies. In the context of Central America, rivers face significant degradation due to pollution, overexploitation, deforestation, climate change, and infrastructure modifications like channelization. This study characterized water quality in the Liberia River (Costa Rica) and Tela watersheds (Honduras), identifying key management challenges. Furthermore, it conducted citizen perception sounding surveys on water management and held water education workshops in schools and communities within these watersheds. The results indicated chronic fecal contamination in all rivers studied in Honduras and Costa Rica, extending to coastal zones. This finding underscores the need for enhanced wastewater infrastructure management and stricter enforcement of water quality standards to protect environmental and community health. Surveys and workshops suggested that targeted water education significantly enhances community knowledge and empowerment, which are critical drivers for improved participatory water governance. Rather than proposing direct policy prescriptions, this study offers conceptual and empirical insights to inform future policy development and support more integrated and sustainable water governance in the region. It also highlights the need for further validation of the proposed river transition curve and emphasizes the importance of community engagement and water education for the protection of river ecosystems in Central America.
DOI: 10.3389/fcosc.2025.16888382026-01-16
Jeff M. Martin, Carter G. Kruse, Tom K. Bragg, Philip M. Urso
Trace minerals found in the diet are essential for animal health, but the role of mineral supplementation in maintaining bison health or boosting immune response is relatively unknown. This study evaluated the impact of an oral drench supplement containing Co, Cu, Se, and Zn—minerals associated with immune function—in reducing mortality and maintaining health in response to a Mycoplasma bovis outbreak in yearling bison. A total of 1,295 mixed-sex, non-reproductive yearlings were studied, with 464 receiving the supplement and 831 serving as controls. Mortality totaled 238 individuals (18.4%), with no statistically significant difference between groups (Pearson’s χ² test, p>0.05), indicating supplement ineffectiveness. Blood analysis confirmed no change in mineral status, suggesting that the supplement formulation, intended for cattle, may not meet bison-specific requirements. Water quality analysis of water sources used in the study revealed elevated Fe and manganese levels, but other mineral imbalances were not evident. Growth rates and final weights did not differ significantly between treatment and control groups, although males consistently outweighed females. Parasitological analyses showed minor differences in gastrointestinal nematode burdens, with no apparent link to supplementation or mortality. Serology results indicated significant differences but were likely of limited biological relevance. Finally, the study highlighted the potential implications of frequent bison handling for research or other purposes, which may increase stress and disease susceptibility. These findings underscore the need for bison-specific mineral information, as well as diagnostic, prevention, and treatment strategies to improve health management in this species.
DOI: 10.3389/fcosc.2025.16890302026-01-16
Sara Jerele, Karyn Bischoff, Erick J. Lundgren, Janet Foley, Erin L. Goodrich
IntroductionVitamin E and selenium are vital micronutrients that play key roles in metabolic functions and antioxidant defense, directly influencing equid health. There are no published reference intervals for concentrations of these micronutrients in healthy donkeys. Methods: We compared serum vitamin E and whole blood selenium concentrations in wild, recently captured donkeys with concentrations in donkeys who had been managed in captivity for at least half a year at the time the blood was drawn. In addition, we assessed hematology and serum biochemistry parameters of a subset of the donkeys. We also indirectly analyzed the diet of wild donkey herds using next-generation sequencing of fecal samples. Our last goal was to establish reference intervals for vitamin E and selenium concentrations in wild and rescued donkeys. To do so, we conducted a cross-sectional study of 113 donkeys from Saline Valley and Butte Valley in Death Valley National Park (DVNP), and captive donkeys from Davis, CA, and San Angelo, TX.ResultsWild donkeys had significantly higher vitamin E concentrations (p < 0.001, difference = 180 μg/dL, CI = 132-228 μg/dL, Tukey multiple comparisons of means test). Captive donkeys, however, had significantly higher selenium concentrations (p < 0.001, difference = 4.97 μg/dL, 95% CI = 3.51-6.43 μg/dL, Tukey multiple comparisons of means test), particularly compared to the wild ones from the Butte Valley population. Reference intervals were established for these micronutrients in wild donkeys. The vitamin E reference range for wild female donkeys was 211-754 μg/dL and for wild male donkeys was 164-780 μg/dL; the selenium reference range for wild female donkeys was 8-21 μg/dL and for wild male donkeys was 12-26 μg/dL. The fecal analysis found a mixed feeding behavior in the wild donkeys, with both grazing and browsing elements, which may explain the relatively high concentrations of these nutrients.DiscussionThis study characterizes the dynamics of vitamin E and selenium concentrations in wild donkeys from Death Valley compared to captive populations, establishing species-specific reference intervals to enhance their management.
DOI: 10.3389/fcosc.2025.1551060